Global Bycatch Nets Some 308,000 Cetaceans a Year

Some 308,000 whales, dolphins and porpoises – collectively known as cetaceans – die each year from entanglement in fishing gear, finds new research by U.S. and British scientists. The study, which was submitted today to the International Whaling Commission (IWC), is the first global estimate of cetacean deaths caused by fishing bycatch.

"This level of bycatch is no doubt significantly depleting and disrupting many populations of whales, dolphins and porpoises," said lead researcher Andy Read of Duke University, who is co chair of World Wildlife Fund’s (WWF) Cetacean Bycatch Task Force.

"Several species will be lost in the next few decades if nothing is done."

WWF is calling on delegates to the IWC meeting – to be held in Berlin, Germany from June 16-20 – to support a resolution on cetacean entanglement deaths that would make the issue a priority for the commission and encourage member governments to provide funding for research and strategies to reduce the problem.

Cetaceans can become entangled in commonly used fishing gear such as gill nets, tangle nets, trammel nets, trawl nets and long lines.

The researchers cite several examples of some cetacean species that are on the brink of extinction because of unintentional death from fishing gear, including right whales, harbor porpoises, Irrawaddy dolphins and a small porpoise known as the vaquita.

Some fifteen percent of the vaquita population is killed every year in fishing nets within the Gulf of Mexico, which is the only place on Earth the endangered porpoise is found. It is primarily gill nets set for mackerels, sharks, rays and other species that unintentionally catch vaquitas.

With a population of only around 500, this practice is decimating the species, the researchers say.

But there is some good news, the researchers report -solutions to the problem of entanglement are available, although they vary by region and species involved.

These can include adding gillie floats that break away when hit by a whale, acoustic "pingers" that warn marine mammals away from nets and buoy lines that are less likely to snare whales and dolphins.

The scientists stress that fishermen have been crucial in developing these successful gear modifications and will be vital to increasing the use of improved gear that limits cetacean bycatch.

They note that concerted efforts have worked, in particular in U.S. fisheries, where cetacean bycatch has been reduced by some two thirds in the past decade.

Bycatch is now recognized as one of the major problems with the industrialization of fishing that has occurred in the past few decades. The United Nations Food and Agriculture Organization estimates that some 25 percent of animals caught in fishing gear dies as bycatch.